104 lines
3.7 KiB
Python
104 lines
3.7 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from taskflow import states as st
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from taskflow.utils import misc
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_WAITING_TIMEOUT = 60 # in seconds
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class FutureGraphAction(object):
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"""Graph action build around futures returned by task action.
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This graph action schedules all task it can for execution and than
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waits on returned futures. If task executor is able to execute tasks
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in parallel, this enables parallel flow run and reversion.
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"""
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def __init__(self, analyzer, storage, task_action):
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self._analyzer = analyzer
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self._storage = storage
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self._task_action = task_action
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def is_running(self):
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return self._storage.get_flow_state() == st.RUNNING
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def is_reverting(self):
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return self._storage.get_flow_state() == st.REVERTING
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def execute(self):
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was_suspended = self._run(
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self.is_running,
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self._task_action.schedule_execution,
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self._task_action.complete_execution,
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self._analyzer.browse_nodes_for_execute)
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return st.SUSPENDED if was_suspended else st.SUCCESS
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def revert(self):
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was_suspended = self._run(
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self.is_reverting,
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self._task_action.schedule_reversion,
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self._task_action.complete_reversion,
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self._analyzer.browse_nodes_for_revert)
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return st.SUSPENDED if was_suspended else st.REVERTED
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def _run(self, running, schedule_node, complete_node, get_next_nodes):
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def schedule(nodes, not_done):
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for node in nodes:
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future = schedule_node(node)
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if future is not None:
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not_done.append(future)
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else:
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schedule(get_next_nodes(node), not_done)
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failures = []
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not_done = []
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schedule(get_next_nodes(), not_done)
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was_suspended = False
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while not_done:
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# NOTE(imelnikov): if timeout occurs before any of futures
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# completes, done list will be empty and we'll just go
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# for next iteration.
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done, not_done = self._task_action.wait_for_any(
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not_done, _WAITING_TIMEOUT)
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next_nodes = []
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for future in done:
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# NOTE(harlowja): event will be used in the future for smart
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# reversion (ignoring it for now).
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node, _event, result = future.result()
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complete_node(node, result)
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if isinstance(result, misc.Failure):
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failures.append(result)
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else:
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next_nodes.extend(get_next_nodes(node))
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if next_nodes:
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if running() and not failures:
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schedule(next_nodes, not_done)
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else:
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# NOTE(imelnikov): engine stopped while there were
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# still some tasks to do, so we either failed
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# or were suspended.
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was_suspended = True
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misc.Failure.reraise_if_any(failures)
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return was_suspended
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